In this episode, the tree house detectives are troubled by a strange tremor in the area, and they decide that they need to investigate earthquakes. They delve into geography, geology, and plate tectonics to discover why they're all shook up. The NASA SCIence Files- series introduces students in grades 3-5 to NASA and integrates mathematics, science, and technology through the use of Problem-Based Learning (PBL), scientific inquiry, and the scientific method. Length: 60:00.